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Publication numberUS6936299 B2
Publication typeGrant
Application numberUS 10/434,165
Publication dateAug 30, 2005
Filing dateMay 9, 2003
Priority dateMay 10, 2002
Fee statusLapsed
Also published asCN1456704A, DE50204021D1, EP1361292A1, EP1361292B1, US20030230138, US20050229847
Publication number10434165, 434165, US 6936299 B2, US 6936299B2, US-B2-6936299, US6936299 B2, US6936299B2
InventorsUlrich Bast, Roman Beyer, Ralph Reiche
Original AssigneeSiemens Aktiengesellschaft
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Determined in situ during coating process using a sensor which has an electrical property which, as a result of the coating process, changes in a manner which is representative of the layer thickness
US 6936299 B2
Abstract
A method and device for layer thickness determination allows for the layer thickness to be determined in situ during the coating process. This is achieved using a sensor which has an electrical property which, as a result of the coating process, changes in a manner which is representative of the layer thickness which has been reached. As such, this property can be measured.
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Claims(7)
1. A method for in situ layer thickness determination during a coating process of a component, comprising:
coating the component and a sensor, wherein the sensor is changed by the coating process such that an electrical property of the sensor, which bears a correlation to the layer thickness, is influenced, and wherein the sensor consists of MCrAlY, where M is an element selected from the group consisting of iron, cobalt and nickel: and
using the change in the electrical property to determine the layer thickness.
2. A method for in situ layer thickness determination during a coating process of a component, comprising:
coating the component and a sensor, wherein the sensor is changed by the coating process, such that an electrical property of the sensor, which bears a correlation to the layer thickness, is influenced, and wherein the sensor is a sintered part; and
using the change in the electrical property to determine the layer thickness.
3. The method as claimed in claim 2, wherein the coating process is an alitizing process.
4. The method as claimed in claim 2, wherein the electrical property is the electrical resistance.
5. The method as claimed in claim 2, wherein the coating process is a chemical vapor deposition process.
6. The method as claimed in claim 2, wherein the coating process is used for the internal coating of a component.
7. A method for in situ layer thickness determination during a coating process of a component, comprising:
changing a sensor by a coating process in such a way that, as a result, an electrical property of the sensor, which bears a correlation to the layer thickness, is influenced; and
using the change in the electrical property to determine the layer thickness, wherein the sensor consists of MCrAlY, where M is an element selected from the group of iron, cobalt and nickel.
Description

The present application hereby claims priority under 35 U.S.C. 119 on European patent application number EP 02010628.2 filed May 10 2002, the entire contents of which are hereby incorporated herein by reference.

FIELD OF THE INVENTION

The invention generally relates to a method and/or device for layer thickness determination.

BACKGROUND OF THE INVENTION

In coating processes, such as for example internal alitizing processes (aluminizing of internal surfaces), the layer thickness is determined by way of a metallographic examination. For this purpose, a wire specimen is introduced into the coating process at a location which is representative of a component which is to be coated. After the coating process has ended, the wire specimen is removed and is then, expensively, cut open and examined. Each coating process is monitored and documented by the use of concomitant working specimens. These measuring and testing methods do not allow coating processes which are not to spec to be corrected as they are ongoing. Therefore, this is a very expensive form of quality assurance.

SUMMARY OF THE INVENTION

It is an object of an embodiment of the invention to provide a method and device for layer thickness determination which solves at least one of the problems outlined above.

An object may be achieved by a method or device in which a sensor is exposed to the coating process in the same way as the component which is to be treated, and an electrical property of this sensor is measured. This property changes as a result of the coating process, so that in situ layer thickness determination during the coating process is possible.

The method is suitable in particular for alitizing processes in which aluminum is introduced into a component (refurbishment).

The electrical resistance is preferably used as a simple electrical measurement variable which is representative of the coating result.

The sensor is, for example, a sintered body, since a sintered body can take up the applied coating material in a representative way (accumulation and diffusion rate). Alternatively, it may be, for example, also porous or, for example, made from the material of the component which is to be coated or from MCrAlY.

The method and/or device is particularly suitable for coating processes in the interior of a component, since these are not readily accessible.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the invention is illustrated in simplified form in the drawings, in which:

FIG. 1 shows a component with a sensor, which component is coated, with the method according to an embodiment of the invention being used for layer thickness determination, and

FIG. 2 shows a measuring arrangement having a sensor for the method according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a hollow component 1 which is to be coated, for example, on an inner surface 4. However, the method can also be used for the in situ layer thickness determination of external surfaces.

A layer 7 of the material M is applied to the inner surface 4 by means of known processes, such as for example CVD (chemical vapor deposition) processes, electrochemical processes or other known coating processes. A sensor 10 is arranged in the cavity 19 of the component 1 and is therefore coated in the same way as the component 1 which is to be treated.

FIG. 2 shows an enlarged view of the sensor 10.

The sensor 10 consists of a material which has an electrical property, such as for example its electrical resistance, impedance, capacitance or the like, which changes as a result of some form of interaction with the material M which forms the layer. The sensor 10 may be of any desired shape, i.e. may, for example, be a piece of wire or in the shape of a small plate.

The sensor 10 is connected to an electrical measuring unit 16 via electrical lines 13; the measuring unit measures the electrical parameter which changes as a result of the sensor 10 being coated with the material M. The way in which the layer thickness is dependent on the electrical variable is known from calibration curves determined in preliminary tests.

The method is used in particular for internal alitizing processes in which aluminum is applied to an inner surface 4 of a component 1 (M=Al). In this case, the sensor consists, for example, of the material MCrAlY (M=Fe, Co, Ni) and changes with the aluminum applied during a CVD process in such a manner that the measured electrical characteristic variable changes in a manner which is representative of the coating result.

List of Reference Symbols

  • 1 Component
  • 4 Inner surface
  • 7 Layer
  • 10 Sensor
  • 13 Electrical line
  • 16 Electrical evaluation/control
  • 19 Cavity

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4898746 *Jun 28, 1988Feb 6, 1990Rca Licensing CorporationMaterial deposition process analysis system
US5057781 *Jul 31, 1989Oct 15, 1991At&T Bell LaboratoriesMeasuring and controlling the thickness of a conductive coating on an optical fiber
US5142228 *Mar 14, 1991Aug 25, 1992Corning IncorporatedMethod for statically or dynamically monitoring the thickness of electrically-conductive coatings on optical fibers
US5466638 *Aug 16, 1994Nov 14, 1995Mitsubishi Denki Kabushiki KaishaMethod of manufacturing a metal interconnect with high resistance to electromigration
US6436246 *Jan 27, 1997Aug 20, 2002Micron Technology, Inc.Using electrical resistance to monitor variations in deposition of conductive metal into trenches of semiconductor wafer; determining when to clean or change collimator
JPH05215290A * Title not available
Classifications
U.S. Classification427/10, 427/248.1, 427/250, 427/237
International ClassificationC23C16/52, C23C4/12, C23C2/14, G01B7/06, C23C4/16, C23C14/54
Cooperative ClassificationC23C4/12, C23C16/52, C23C14/545, C23C4/16, C23C2/14, G01B7/06
European ClassificationC23C4/12, C23C2/14, C23C16/52, G01B7/06, C23C14/54D6, C23C4/16
Legal Events
DateCodeEventDescription
Oct 20, 2009FPExpired due to failure to pay maintenance fee
Effective date: 20090830
Aug 30, 2009LAPSLapse for failure to pay maintenance fees
Mar 9, 2009REMIMaintenance fee reminder mailed
Jul 14, 2003ASAssignment
Owner name: SIEMENS AKTIENGESELLSCHAFT, GERMANY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BAST, ULRICH;BEYER, ROMAN;REICHE, RALPH;REEL/FRAME:014262/0222;SIGNING DATES FROM 20030509 TO 20030519